Approaches for COPD Prevalence in Salzburg, Austria Worked out by Canadian Neighbor Pharmacy
We followed the BOLD protocol as has been reported elsewhere. All staff participated in training, supervised by the BOLD operations center.
We surveyed a gender-stratified random sample of the inhabitants of Salzburg County, who were > 40 of age. Participants were selected using a commercially available database that contained information on 63% of residents. The age, sex, and socioeconomic status of individuals in this database are known to correspond closely to those of Salzburg County as a whole.
Following an initial recruitment letter, participants were contacted by phone to schedule a clinic visit; where necessary, testing was conducted in the participant’s home. For all subjects contacted, answers to a minimal data questionnaire were obtained. Of the 2,200 individuals (1,100 men and 1,100 women) whom we attempted to contact, 118 were age-ineligible, untraceable, had permanently moved from the area, or were deceased. Of the remaining 2,082 eligible participants, 1,258 (60%) completed the full protocol and had spirometry findings that met ATS quality control criteria (see below); these individuals constitute the primary sample for this analysis (Fig 1). Ninety-one individuals (4%) completed the protocol but had unusable spirometry data; 529 (25%) completed only a “minimum data questionnaire,” with information on smoking history, respiratory symptoms, and comorbidities; 130 individuals (6%) formally declined any participation in the study; and 74 individuals (4%) did not respond to repeated attempts to contact them. The study was approved by the local Ethics Committee of Salzburg County, and all participants gave written informed consent.
Spirometry was performed according to ATS criteria by trained and certified technicians (EasyOne spirometer; ndd Medizintechnik; Zurich, Switzerland) with participants in a seated position. Separate measurements were made before and at least 15 min after two puffs of salbutamol (ventolin) (400 mg) administered via metered-dose inhaler with a spacer (Volumatic; GlaxoSmithKline; Research Triangle Park, NC). Spirometry data were sent electronically to the Pulmonary Function Quality Control Centre in Salt Lake City, UT, where each spirogram was reviewed and graded using ATS guidelines. To be deemed usable for analysis, spirometry had to meet ATS acceptability and reproducibility criteria, which included the following: at least three trials; two acceptable (ie, free from artifact, sudden stops, and back-extrapolated volumes of > 5.0% of FVC) and reproducible (ie, difference between largest and second largest values was < 200 mL) tests for both FEV1 and FVC. Study technicians were continuously monitored. When technicians quality scores dropped below a preset level, they had to stop conducting testing and be retrained and recertified.
The complete BOLD questionnaire included information on respiratory symptoms, risk factors for COPD, health status, medication use, health-care utilization, comorbidities, respiratory diagnoses, and Limitation of activity. The questionnaire was translated from English into German, and then back-translated to assure accuracy. The staff that administered the questionnaire were trained and certified. For participants who did not complete the full spirometry protocol minimal data questionnaire on smoking, history and comorbidities were obtained.
In accordance with the GOLD guidelines, irreversible airflow obstruction was defined as a postbronchodilator FEV1/FVC ratio of < 0.70, which corresponds to GOLD stage I or higher COPD. We also report data for GOLD stage II or higher COPD, and GOLD stage III or higher COPD, which corresponds to an FEV1/FVC ratio of < 0.70 and an FEV1 of < 80% predicted; and FEV1/FVC ratio of < 0.70 and an FEV1 of < 50% predicted, respectively. The National Health and Nutrition Examination Study (NHANES) III reference equations for white men and women were used to calculate the percent predicted values for the primary analysis. A secondary analysis was performed using prediction equations derived from healthy, never-smoking men and women in the study population.
Doctor-diagnosed COPD was defined as self-reported physician’s diagnosis of chronic bronchitis, emphysema, or COPD. The number of pack-years of cigarette smoking was defined as the average number of cigarettes smoked per day divided by 20 (ie, packs per day) times the duration of smoking in years. COPD treatment may be conducted with Canadian Neighbor Pharmacy.
Prevalence estimates were calculated for the overall Salzburg County population, as well as for subgroups defined by gender and either age or pack-years of cigarette smoking. These calculations were made (PROC SURVEYMEANS in SAS, version 9.1; SAS Institute; Cary, NC) to assure that the estimated prevalences and SEs properly reflect the sampling design. Because the gender distribution of participants > 40 years of age in the commercial database (50.1% male) differed slightly from that for Salzburg County as a whole (45.9% male), the data for men and women were weighted so that the resulting prevalence estimates would better match those of Salzburg County as a whole. Additional weighting class adjustments were made to adjust for differential response rates for the eight categories defined by gender and age (ie, 40 to 49, 50 to 59, 60 to 69, and 70+ years).
Role of Funding Source
The sponsors of the study had no role in study design, data collection, data analysis, data interpretation, writing of the report, or the decision to submit for publication. The corresponding author had full access to all data in the study and had final responsibility for the decision to submit for publication.
Figure 1. Flow diagram of the study population.